remove s3 bucket polling when waiting for transformation results

[MattShirley]

Client side work for ssl-hep/ServiceX#1049

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.26%. Comparing base (9c1849d) to head (4e01dee).
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #587      +/-   ##
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+ Coverage   96.20%   96.26%   +0.06%     
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  Files          29       29              
  Lines        1870     1902      +32     
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+ Hits         1799     1831      +32     
  Misses         71       71              

Flag	Coverage Δ
unittests	96.26% <100.00%> (+0.06%)	⬆️

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[Copilot]

Pull Request Overview

Client-side removal of Minio bucket polling in favor of ServiceX’s direct results API, with corresponding adapter support and test updates.

• Added get_transformation_results method to the ServiceX adapter and wired it into download logic.
• Updated core query logic (download_files) to pass a begin_at timestamp and call the new API instead of polling Minio.
• Refactored tests to mock servicex.get_transformation_results and added unit tests covering its success and error responses.

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
tests/test_servicex_dataset.py	Replaced mock_minio.list_bucket with servicex.get_transformation_results mocks and reset calls
tests/test_servicex_adapter.py	Imported datetime and added async tests for get_transformation_results handling 200/403/404/500 statuses
tests/test_dataset.py	Passed new begin_at argument to download_files and mocked the ServiceX results API
servicex/servicex_adapter.py	Implemented get_transformation_results method with status‐code checks
servicex/query_core.py	Updated transform_complete and download_files to accept and forward begin_at and call the new API

Comments suppressed due to low confidence (1)

tests/test_servicex_dataset.py:209

• The string literal for request_id has mismatched quotes and includes an extra trailing double quote; this will likely cause the test to fail. Use consistent quoting, for example "123-456-789".

servicex.submit_transform.return_value = {"request_id": '123-456-789"'}

[ponyisi]

This relies on being kept in line with the transformer sidecar, and I think it may fail in certain cases (like the parquet output format is selected). Should we add a new field in the transform_result table that stores the object_name as uploaded to S3 (as determined by https://github.com/ssl-hep/ServiceX/blob/1991e6b2ea00dcbd8cdb9b9ed32fd44049f0dea3/transformer_sidecar/src/transformer_sidecar/transformer.py#L349 etc.) ?

[BenGalewsky]

This is relying on synchronization of clocks between the client and the server. Wouldn't it be better to set new_begin_at to be the latest result timestamp we see in the transform_results?